A quick guide on gear tooth clearance;
No blood = too loose.
Aircraft Mechanic passes out = too tight.
Moderate bleeding = acceptable clearance.
Note to builders: When turning engine over by gripping flywheel, avoid the 10 and 2 O’clock grip because it puts the right thumb very close to the point where the starter and ring gear mesh. Proper mesh clearance is set with a 1/16″ drill in in a separate operation, thumb is not an accepted substitute for 1/16″ drill.